1. Filed of Invention
The invention relates to a housing for holding electrical and/or electronic components, with a housing opening and with an entry fitting which is rotationally located in the housing opening, the entry fitting having a cylindrical holding part in which an annular groove is formed, and being held by a fastener in the housing. In addition, the invention relates to an entry fitting for rotary arrangement in the opening of a housing of an electrical or electronic device, especially an optical, inductive or capacitive proximity switch.
2. Description of Related Art
The initially described housing can be especially the housing of a sensor, for example, of an inductive, capacitive or optical proximity switch. Within the housing, there are the actual sensor element and other electrical and electronic components, for example, an evaluation circuit. For electrical connection to other devices, for example, a central control, the housing has an entry fitting which is used as a cable or plug outlet.
Such a housing is known for example from German Patent DE 197 18 392 C2. In the known housing, the entry fitting has a snap projection with a slotted locking bead, using which the entry fitting can be locked in the housing opening. In addition to this snap connection, on the housing, there are undercuts and on the entry fitting, there are stabilization shoulders which can be caused to engage the undercuts and which are made complementary to the undercuts. The execution of the undercuts and the stabilization shoulders which additionally connect the entry fitting and the housing to one another results in that the forces acting on the entry fitting no longer need be accommodated solely by the snap connection.
In order to prevent unintentional detachment of the entry fitting from the housing opening, it is moreover provided that, from the housing interior, a cylindrical blocking element is placed in the snap projection, by which it is ensured that the locking bead of the snap projection cannot move radially to the inside, by which detachment of the snap connection would occur. By the above described measure, the entry fitting can be securely anchored to the housing, but for this reason, a very special execution both of the housing and also of the entry fitting is necessary.
Another housing of the initially described type is known from German Patent DE 199 52 643 C1. In this housing, an entry fitting can also be selectively attached in different positions in the housing opening. Here, the housing opening is made as a hub hole, and the entry fitting can be fixed by means of a locking clip which is integrated on the housing cover and/or on the housing bottom. The locking clips have catch hooks, by means of which the entry fitting can be fixed in different rotary positions. The approach described in German Patent DE 199 52 643 C1 also requires a special configuration of the housing, especially of the housing cover and/or of the housing bottom.
Finally, German Patent DE 101 19 910 C1 discloses a housing with an entry fitting which is located to be able to turn in the housing opening, in which to fix the entry fitting in a first or a second rotary position, there is an insertion part which is fixed in the housing interior, with an insert, the insert being surrounded by the cylindrical holding part of the entry fitting, and there being catch means which interact on the holding part and the insert.
It is common to all known housings that the catching and fixing of the entry fitting in the housing opening must take place with an at least partially opened housing, i.e., the housing can only be closed after installation of the entry fitting. If the housing, as stated initially, is the housing of a proximity switch, based on the conditions of use of the proximity switch, it is often necessary for the proximity switch to be potted for protection of the electrical and electronic components which are located in the housing. However, potting of a proximity switch is, of course, only possible when all electrical and electronic components are located in the housing and the housing, except for an opening for adding the potting resin, is sealed. Therefore, in the known housings, installation of the electrical and electronic components, and especially the potting of the housing, are possible only after installation of the entry fitting.
Due to the plurality of different proximity switch versions which are used in practice, there is a requirement for making the proximity switch as modular as possible in order to reduce the number of the proximity switches kept in a warehouse. For example, otherwise identical proximity switches can differ only in that they have a plug outlet, a cable outlet or a terminal space for the wires of an electrical cable. To do this, differently made entry fittings are necessary. In a modular structure of the actual housing and of the entry fitting, the two components could be produced and stored separately from one another, and accordingly, assembled only when necessary.